Paper feed control mechanisms

ABSTRACT

A duplicating machine of the type employing a table for holding a stack of paper sheets. The machine includes feed mechanisms which engage the top sheet of the stack and thereby feed the sheets one at a time to the duplicating mechanisms of the machine. The particular improvement of the invention involves an automatic control means for the operation of the feed member, the control means being dependent upon the location of the top of the stack. The control means include a latch lever connected to a support for feed rollers or other feed members, and the latch lever moves with the feed member support as the feed member changes position in response to a change in the height of the stack. When the height of the stack reaches a predetermined position, the latch lever engages the means for driving the feed member to automatically stop the feeding operation. The automatic operation occurs whenever the amount of paper in the stack is reduced beyond a predetermined level or when the table is deliberately lowered. The latch lever is automatically released for resumption of the feeding operation when the stack height is raised above the predetermined level.

[ May 13, 1975 PAPER FEED CONTROL MECHANISMS for holding a stack ofpaper sheets. The machine int L cludes feed mechanisms which engage thetop sheet of [75] lnvemor' John L Swanson Llber yvlne the stack andthereby feed the sheets one at a time to [73] ASSigneeI c Comp y, Niles.the duplicating mechanisms of the machine. The particular improvement ofthe invention involves an auto- }l22] Flled' July 1973 matic controlmeans for the operation of the feed [21] Appl. No.: 379,549 member, thecontrol means being dependent upon the location of the top of the stack.The control means in- [52] U 5 Cl 27l/ll0 271/116 271/117 clude a latchlever connected to a support for feed rol- [51] B65h 3/06 lers or otherfeed members, and the latch lever moves [58] Fieid 116 I17 with the feedmember support as the feed member 10 l l changes position in response toa change in the height of the stack. When the height of the stackreaches a References Cited predetermined position, the latch leverengages the means for driving the feed member to automatically UNITEDSTATES PATENTS stop the feeding operation. The automatic operation6/1940 271/] 17 c s whenever the amount of paper in the stack is UnitedStates Patent Swanson PATENTED HAY 1 3975 3,883,132

SHEET 10F 3 FIG: 1

FIG. 2

PAPER FEED CONTROL MECHANISMS This invention is directed to improvementsin duplicating equipment. In particular, the invention relates toduplicators, printing presses, and related equipment incorporatingfeeding mechanisms which are adapted to feed individual sheets from astack of sheets located in or adjacent the equipment.

In typical duplicating machines, a table is provided for supporting astack of paper sheets. Feeding mem bers, usually feed rollers, areprovided for engaging the top sheet in a stack for thereby feeding thesheet into position for a copying operation. The feeding mechanisms aredriven in a repetitive fashion so that a continuous movement of theindividual sheets is achieved.

In previous duplicating equipment, the operator would locate a stack ofpaper on the feed table and then turn a knob or perform some otheroperation which would raise the table and the associated stack of paperto the feed level. Once the feed level is reached, the operator thenturned on the feeding mechanisms. This could result in a misfeed if theoperator accidentally turned on the paper feed first and then operatedthe table raise mechanism.

After operation of the duplicating machine for a period of time, itbecomes necessary to replenish the supply of paper. In previousequipment, this is accomplished by turning off the feed mechanisms atwhich time the feed table can be lowered, the paper replenished, thefeed table raised to the feed position, and the feed mechanism thenturned back on.

It is a general object of this invention to provide improvements overprevious duplicating equipment with respect to the mechanisms employedfor achieving operation of paper feeding mechanisms.

It is a more specific object of this invention to provide improvementsin feeding mechanisms for duplicating machines whereby requirements'forturning feeding mechanisms on and off in order to supply and replenishpaper are significantly reduced.

It is a still further object of this invention to provide automaticpaper feed on-off mechanisms which can be efficiently incorporated induplicating equipment whereby the operator time required for duplicatingis reduced.

These and other objects of this invention will appear hereinafter andfor purposes of illustration, but not of limitation, specificembodiments of the invention are shown in the accompanying drawings inwhich:

FIG. 1 is a side elevation of a duplicating machine;

FIG. 2 is a plan view of the duplicating machine shown in FIG. 1;

FIG. 3 is an enlarged detail view illustrating the feed and automaticlatch mechanisms employed in the construction of the invention;

FIG. 4 is a further detail view illustrating portions of the feed andlatch mechanisms;

FIG. 5 is a fragmentary view ofa feed roller and associated support anddrive mechanisms taken about the line of 5-5 of FIG. 3; and,

FIGS. 6, 7 and 8 comprise additional detail views of portions of thefeed and latch mechanisms utilized in the construction.

The apparatus of the invention generally comprises a duplicating machinehaving a table for holding a stack of paper sheets. At least one feedroller or other feed member is provided for engaging the top sheet of astack and drive means are employed for operating the feed member so thatthe sheets are fed one at a time to a duplicating position.

A latch lever is operatively connected to a support for the feed member,and this support moves with the feed member as the height of the paperstack changes. Thus, the support will gradually drop as the sheets areremoved one at a time from the table. In addition, the feed membersupport will drop whenever the table is lowered, for example when thestack of sheets is being replenished.

The latch lever associated with the feed member support is adapted tomove into engagement with the drive means for the feed member wheneverthe support has moved to a predetermined position. Engagement of thelatch lever with the drive means operates to disable the drive meanswhereby the feeding operation is automatically stopped when thepredetermined level is reached, there being no requirement for anoperator to independently actuate a stop mechanism. In cases where thefeeding operation is stopped with the table being lowered to enablereplenishing of paper supply, the latch lever will be automaticallydisengaged when the table is raised to the operating position. Again,there is no necessity for independent action by an operator to restartthe mechanism once the paper supply has been replenished.

The accompanying drawings illustrate a duplicating machine 10 which maybe any one of several existing types of machines. A table top machine isillustrated; however, the concepts of the invention are applicable tolarger machines and to printing presses and duplicating equipment ofmany other types. I

In accordance with the design of previous equipment, the machineincludes a feed table 12 which will support a stack of paper sheets. Apair of feed rollers 14 are mounted on a shaft 16 of rectangular crosssection, and this shaft is journalled at one end to the support member18. The opposite end of the shaft is received within the support housing20, this housing including drive mechanisms to be described.

The paper sheets fed into the duplicating machine are moved byappropriate conveyor means to a duplicating position and are thendischarged onto the table 22. A knob 24 is provided for controlling themovement of the table 12 with a ratchet and pinion arrangement, forexample of the type shown in Zahradnik US. Pat. No. 3,273,884, beingsuitably employed for achieving a raising and lowering operation. A maincontrol knob 26 is employed for starting the various op eratingmechanisms including the feed drive mechanisms.

The details of the drive and latch mechanisms comprising a preferredform of the invention are illustrated in FIGS. 3 through 8. Thesemechanisms include a drive cam 28 which is tied to a continuouslyrotating shaft connected to a main drive motor for the machine. The lobe30 of the cam is adapted to engage the roller 32 mounted at the end ofdrive lever arm 34. The lever arm 34 is pivoted about stub shaft 36which may be attached to the duplicator housing.

A drive arm 38 is tied to lever 34 through sleeve 40 whereby pivotingmovement of the lever 34 about shaft 36 results in swinging reciprocalmovement of the drive arm 38. A drive link 42 is connected to the arm 38by means of an adjustable pin 44 received in the slot 46 defined at theend of the drive arm. The adjustability of the position of the pin 44relative to the slot 46 permits adjustment of the drive stroke impartedby the arm 38.

The opposite end of link 42 is attached to crank arm 48 by means of apin 50, the pin being rotatable relative to the link. Accordingly, thereciprocal movement which is imparted to the link 42 results in aswinging reciprocal movement for the crank arm 48.

A shaft 52 supporting crank arm 48 also supports a segment gear 54, thelatter being integrally formed with the crank arm. This segment gearmeshes with idler gear 56 which in turn drives gear 58. The latter, asshown in FIG. 5, fits around the end 60 of the shaft 16, and pins 62secure this gear to a one-way over-running clutch 64.

In the feeding operation of the mechanisms illustrated, the cam 28continuously pivots the lever 34, and the resulting swinging movement ofdrive arm 38 causes swinging movement of segment gear 54 through theoperation of link 42 and crank arm 48. The gears 56 and 58 rotate backand forth in response to the movement of the segment gear. Since thegear 58 is not tied to the shaft 16, the movement of this gear affectsonly the clutch 64 and, therefore, the shaft 16 and associated feedrollers 14 rotate in only one direction. Considering FIGS. 3 and 4, thisfeed roller rotation is clockwise whereby a sheet in paper stack 66 isfed into the duplicating machine during each revolution of the cam Thesupports 18 and for the opposite ends'of the shaft 16 are connected tothe machine housing for pivoting movement about opposing stub shafts 68.The shaft 52 supporting segment gear54 and the integrally formed crankarm 48 comprises an extension of the stub shaft 68 which carries thesupport 20. The supports 18 and 20 move about their respectiveconnections depending upon the height of the paper stack so that therollers 14 will continue to engage the top sheet in a stack as theheight of the stack decreases during feeding.

An outwardly extending ear 70 is formed in the support 20 and a nut 72is secured to this ear. Adjusting screw 74 is received by the nutwhereby the end of the screw can be moved toward and away from the ear.A lever 76 is also mounted on stub shaft 68, and a tab 78 at one end ofthis lever provides a connection for tension spring 80. A pin 82 whichis attached to the machine frame secures the opposite end of the spring,and spring action serves to force the tab 19 at the other end of thelever 76 into engagement with the end of the screw 74. Accordingly, thelever 76 will follow the movement of the supports 18 and 20 with thespecific relationship of the lever 76 and the supports being determinedby the position of the adjusting screw 74.

An additional tension spring 84 has one end connected to pin 86 carriedby the lever 76. The opposite end of this spring is attached to pin 88carried by lever 90. The lever 90 is pivotally mounted on a stub shaft92 which is carried by latch lever 94. A tab 96 at the end of lever 90engages the end of adjusting screw 98 which is threadably received bythe nut 100 carried on the car 102 formed in the latch lever 94. Thelatch lever 94 defines a hook end 106 which is maintained in spacedrelationship relative to the ear 108 formed in drive arm 34 during thefeeding operation.

A third spring 110 is connected at one end to pin 112 carried by lever76 and the other end of this spring is connected to a tab 114 carried bythe lever 90. The spring 110, therefore, urges the lever 90 intoengagement with the spring pin 112 (see FIG. 4). At the same time, thespring 84 urges the latch lever 94 to pivot in a counterclockwisedirection toward the lever 90 thereby normally urging the screw 98 intoengagement with the ear 96.

The roller 32 which bears against the cam 28 is normally urged intoengagement with the cam by means of spring 118. This spring has one endconnected to pin 120 located on the arm 38, and the other end isconnected to pin 122 which is secured to the machine frame. The spring118 operates to urge the assembly of the drive lever 34 and the arm 38in a counterclockwise direction so that the roller 32 will always bearagainst the cam 28 unless the lever arm 34 is latched against pivotingmovement.

In the operation of the construction illustrated, the supports 18 and 20will pivot in a clockwise direction either gradually during the courseof a feeding operation or abruptly if the table 12 is lowered. In eithercase, the adjusting screw 74 will bear against lever 76 to pivot thislever clockwise relative to the drive lever 34. This, in turn, willcause the spring 110 to pull the lever 90 for pivoting of this leverclockwise about shaft 92. This action causes the lever 90 to beardownwardly on adjusting screw 98 which causes the hook end 106 of thelatch lever 94 to move toward the ear 108.

In the illustrated embodiment, the roller 32 is engaged with the lobe ofcam 28 whereby the ear 108 of lever 34 is in its lowest position. As thecam movement continues, the roller 32 will follow the cam surfacethereby moving the ear 108 upwardly as the lever 34 pivots about theaxis 36. If, however, the hook end 106 of the latch lever 94 is movedsufficiently to engage the car 108, the ear and the associated lever 34will be restrained against pivoting movement. The cam 28 will continueto rotate; however, the lever 34 will remain stationary thereby shuttingoff any drive to the rollers 14. This latching action occursautomatically in response to lowering of the height of the paper stacksince the height of the stack controls the position of the supports 18and 20 which, in turn, control the position of the latch lever 94.Disabling of the drive movement occurs automatically when the supportsare lowered,

' and it will be appreciated that disengagement of the latch lever withthe ear 108 will also occur automatically when the position of the topof the paper stack is raised to the extent that pivoting movement of thesupport will move the latch lever out of contact with the ear 108.

With the arrangement shown, the operator need only operate the maincontrol knob 26 at the outset of a duplicating operation. If theduplicating operation is al lowed to progress to the point that thepaper is depleted or the height thereof has dropped below an operatinglevel, then the feeding operation will automatically stop even thoughthe cam 28 will continue to rotate. In this connection, an audio orvisual signal may be utilized to advise the operator that a replenishingof the paper supply is necessary.

After replenishing the paper supply, the operator simply raises thetable to the desired height, and the feeding operation will commence assoon as the top of the paper stack reaches a predetermined position. Inother circumstances, it may be desirable to lower the table before thepaper stack has been depleted to the extent that the feeding mechanismsare disabled. Under these circumstances, the lowering of the table bymeans of the knob 24 will itself result in shutting off of the feedingoperation.

The levers 76 and 90 operate as position control le vers in thearrangement described. Thus, the adjusting screw 74 varies the relativepositions of the lever 76 and support while the adjusting screw 98varies the relative positions of the lever 90 and latch lever 94. Theserelative positions determine the point at which the latch lever willengage the drive lever 34 as the support 20 moves downwardly inaccordance with the paper height.

The described arrangement also provides for adjustment of the feedroller action. Specifically, adjustment of the pin 44 along the slot 46changes the effective lever arm of the arm 38 thereby affecting theangular motion imparted to the segment gear 54 which controls the feedroller rotation. With this arrangement, the distance of movement of thetopmost sheet into the machine is readily controlled.

The lever arm 90 defines a hooked end 124 which is connected to thetable raising mechanism. The construction of the invention may utilize astandard paper stack height sensing mechanism. Specifically, the lever90 normally is latched to a table raising power lever (not shown) whichis periodically released by movement of the lever 90 as the latterpivots in response to lowering of the paper stack height. Such powerlever permits a drive for the paper stack table to operate and raise thetable until the lever 90 is again latched.

The construction illustrated includes a latch 116 which is adapted toengage an additional car 119 carried by the drive lever 34. The latch116 is connected to control knob 26, and pivoting of the latch in acounterclockwise direction from the position shown in FIGS. 3 and 4 willoperate to free the drive arm for feeding movement. Thus, release of thelatch 116 is required at the outset of the duplicating operation withthe control of the feeding being thereafter determined by the positionof the supports 18 and 20. It will be appreciated that the position ofthe latch 116 in FIGS. 3 and 4 will prevent any feeding operation sincethis latch will hold the drive lever 34 stationary so that the roller 32cannot follow the cam 28.

It will be understood that various changes and modifications may be madein the above described construction which provide the characteristics ofthe invention without departing from the spirit thereof particularly asdefined in the following claims.

' That which is claimed is:

1. In a duplicating machine including a table for holding a stack ofpaper sheets, at least one feed member for engaging individual sheets tofeed the sheets to the duplicating mechanisms, means for driving thefeed member for achieving the feeding operation, and primary means forcontrolling the operation of the means for driving the feed member, theimprovement comprising secondary control means for automatically controlling the feeding operation of the feed member depending upon thelocation of the top of said stack, said control means including a latchlever, means operatively connecting said latch lever to said feedmember, said latch lever moving with said feed member as the feed memberchanges position in response to a change in the height of said stack,the movement of the latch lever resulting in engagement of the latchlever with the means for driving said feed member when the top of thestack reaches a predetermined position, the engagement of the latchlever with the means for driving the feed member stopping the driving ofthe feed member.

2. A mechine in accordance with claim 1 including a support for saidfeed member, said means operatively connecting said latch leverincluding said support, and said support being movable with said feedmember as the feed member moves in response to changes in location ofthe top of said stack.

3. A machine in accordance with claim 2 wherein said feed membercomprises at least one feed roller, said support comprising means forjournalling the feed roller, said drive means including a clutch wherebysaid feed roller is adapted to rotate in only one direction forachieving successive feeding of the individual sheets.

4. A construction in accordance with claim 3 wherein said drive meansinclude a cam and a drive lever, the cam engaging one end of said drivelever, said cam imparting pivoting movement to said drive lever duringeach rotation of the cam, gear means operatively connected to said drivelever whereby rotary movement is imparted to said gear means duringpivoting movement of the drive lever, said gear means being connectedto,

said feed roller through said clutch means.

5. A machine in accordance with claim 4 wherein said latch lever isadapted to move into engagement with said drive lever, said latch leverpreventing pivoting movement of said drive lever when engaged with thedrive lever.

6. A machine in accordance with claim 1 wherein said feed membergradually follows the top of said stack as the location of the top ofsaid stack changes upon removal of successive sheets from the stack.

7. A machine in accordance with claim 1 wherein said table is adjustablymounted, said feed member moving in response to lowering of the tableduring replacement of paper on the table whereby said feed member stopsoperation when the table is lowered, and wherein said latch lever isautomatically disengaged when the table is raised after replacement ofpaper on the table.

8. In a duplicating machine including a table for holding a stack ofpaper sheets, at least one feed member for engaging individual sheets tofeed the sheets to the duplicating mechanisms, means for driving thefeed member for achieving the feeding operation, and primary means forcontrolling the operation of the means for driving the feed member, theimprovement comprising means for automatically controlling the feedingoperation of the feed member depending upon the location of the top ofsaid stack, said control means ineluding a latch lever, a support forsaid feed member, said latch lever being connected to the support andsaid support and latch lever being movable with said feed member as thefeed member moves in response to V changes in location of the top ofsaid stack, the movethereby vary the predetermined position at whichsaid latch lever engages said means for driving said feed member.

9. A machine in accordance with claim 8 wherein said position controllever means include a first lever, spring means urging said first leveragainst said support, and an adjustable screw carried by the support forvarying the relative position of said first lever and the support.

l0.-A machine in accordance with claim 9 including an additionaladjusting screw carried by said latch lever, a second position controllever engaging said additional adjusting screw, and additional springmeans connecting said second position control lever and said latchlever, said additional adjusting screw operating to vary the relativepositions of said second position control lever and said latch lever inopposition to said additional spring means.

11. In a duplicating machine including a table for holding a stack ofpaper sheets, at least one feed member for engaging individual sheets tofeed the sheets to the duplicating mechanisms, means for driving thefeed member for achieving the feeding operation, and primary means forcontrolling the operation of the means for driving the feed member, theimprovement comprising means for automatically controlling the feedingoperation of the feed member depending upon the location of the top ofsaid stack, said control means including a latch lever, a support forsaid feed member, said latch lever being connected to the support andsaid support and latch lever being movable with said feed member as thefeed member moves in response to changes in location of the top of saidstack, said feed member comprising at least one feed roller, saidsupport comprising means for journalling the feed roller, said drivemeans including a clutch whereby said feed roller is adapted to rotatein only one direction for achieving successive feeding of the individualsheets, the movement of the latch lever resulting in engagement of thelatch lever with the means for driving said feed member when the top ofthe stack reaches a predetermined position, the engagement of the latchlever with the means for driving the feed member stopping the driving ofthe feed member, said means for driving including a cam and a drivelever, the cam engaging one end of said drive lever, said cam impartingpivoting movement to said drive lever during each rotation of the cam,gear means operatively connected to said drive lever whereby rotarymovement is imparted to said gear means during pivoting movement of thedrive lever, said gear means being connected to said feed roller throughsaid clutch means, said gear means including a reciprocally movablesegment gear, a drive arm connected to said drive lever for impartingdriving force to the segment gear, and means for adjusting the effectivelength of said drive arm to thereby vary the angular rotation of thesegment gear for in turn varying the feed rotation of said feed roller.

12. In a duplicating machine including a table for holding a stack ofpaper sheets, at least one feed member for engaging individual sheets tofeed the sheets to the duplicating mechanisms, means for driving thefeed member for achieving the feeding operation, and primary means forcontrolling the operation of the means for driving the feed member, theimprovement comprising secondary control means for automaticallycontrolling the feeding operation of the feed member depending upon thelocation of the top of said stack, said control means including a latchlever, means operatively connecting said latch lever to said feedmember, said latch lever moving with said feed member as the feed memberchanges position in response to a change in the height of said stack,the movement of the latch lever resulting in disengagement of the latchlever with the means for driving said feed member when the top of thestack reaches a predetermined position, the disengagement of the latchlever with the means for driving the feed member starting the driving ofthe feed member.

13. A machine in accordance with claim 12 including a support for saidfeed member, said means operatively connecting said latch leverincluding said support, and said support being movable with said feedmember as the feed member moves in response to changes in location ofthe top of said stack.

14. A machine in accordance with claim 13 wherein said feed membercomprises at least one feed roller, said support comprising means forjournalling the feed roller, said drive means including a clutch wherebysaid feed roller is adapted to rotate in only one direction forachieving successive feeding of the individual sheets.

15. A construction in accordance with claim 14 wherein said drive meansinclude a cam and a drive lever, the cam engaging one end of said drivelever, said cam imparting pivoting movement to said drive lever duringeach rotation of the cam, gear means operatively connected to said drivelever whereby rotary movement is imparted to said gear means duringpivoting movement of the drive lever, said gear means being connected tosaid feed roller through said clutch means.

16. A machine in accordance with claim 15 wherein said latch lever isadapted to move into engagement with said drive lever, said latch leverpreventing pivoting movement of said drive lever until disengaged fromthe drive lever.

17. A machine in accordance with claim 12 wherein said feed membergradually follows the top of said stack as the location of the top ofsaid stack changes upon removal of successive sheets from the stack,

18. A machine in accordance with claim 12 wherein said table isadjustably mounted, said feed member moving in response to lowering ofthe table during replacement of paper on the table whereby said feedmember stops'operation when the table is lowered, and wherein said latchlever is automatically disengaged when the table is raised afterreplacement of paper on the table.

19. In a duplicating machine including a table for holding a stack ofpaper sheets, at least one feed member for engaging individual sheets tofeed the sheets to the duplicating mechanisms, means for driving thefeed member for achieving the feeding operation, and primary means forcontrolling the operation of the means for driving the feed member, theimprovement comprising means for automatically controlling the feedingoperation of the feed member depending upon the location of the top ofsaid stack, said control means including a latch lever, a support forsaid feed member, said latch lever being connected to the support andsaid support andlatch lever being movable with said feed member as thefeed member moves in response to changes in location of the top of saidstack, the movement of the latch lever resulting in disengagement of thelatch lever with the means for driving said feed member when the top ofthe stack reaches a predetermined position, the disengagement of thelatch lever with the means for driving the feed member starting thedriving of the feed member, and wherein said means connecting said latchlever to said support comprises position control lever means movablewith said support, said position control lever means including adjustingmeans for varying the relative positions of said support and said latchlever to thereby vary the predetermined position at which said latchlever engages said means for driving said feed member.

20. A machine in accordance with claim 19 wherein said position controllever means include a first lever, spring means urging said first leveragainst said support, and an adjustable screw carried by the support forvarying the relative position of said first lever and the support.

21. A machine in accordance with claim 20 including an additionaladjusting screw carried by said latch 1ever, a second position controllever engaging said additional adjusting screw, and additional springmeans connecting said second position control lever and said latchlever, said additional adjusting screw operating to vary the relativepositions of said second position control lever and said latch lever inopposition to said additional spring means.

22. In a duplicating machine including a table for holding a stack ofpaper sheets, at least one feed memher for engaging individual sheets tofeed the sheets to the duplicating mechanisms, means for driving thefeed member for achieving the feeding operation, and primary means forcontrolling the operation of the means for driving the feed member, theimprovement comprising means for automatically controlling the feedingoperation of the feed member depending upon the location of the top ofsaid stack, said control means including a latch lever, a support forsaid feed member, said latch lever being connected to the support andsaid support and latch lever being movable with said feed member as thefeed member moves in response to changes in location of the top of saidstack, said feed member comprising at least one feed roller, saidsupport comprising means for journalling the feed roller, said drivemeans including a clutch.whereby said feed roller is adapted to rotatein only one direction for achieving successive feeding of the individualsheets, the movement of the latch lever resulting in disengagement ofthe latch lever with the means for driving said feed member when the topof the stack reaches a predetermined position, the disengagement of thelatch lever with the means for driving the feed member starting thedriving of the feed member, said means for driving including a cam and adrive lever, the cam engaging one end of said drive lever, said camimparting pivoting movement to said drive lever during each rotation ofthe cam, gear means operatively connected to said drive lever wherebyrotary movement is imparted to said gear means during pivoting movementof the drive lever, said gear means being connected to said feed rollerthrough said clutch means, said gear means including a reciprocallymovable segment gear, a drive arm connected to said drive lever forimparting driving force to the segment gear, and means for adjusting theeffective length of said drive arm to thereby vary the angular rotationof the segment gear for in turn varying the feed rotation of said feedroller.

1. In a duplicating machine including a table for holding a stack ofpaper sheets, at least one feed member for engaging individual sheets tofeed the sheets to the duplicating mechanisms, means for driving thefeed member for achieving the feeding operation, and primary means forcontrolling the operation of the means for driving the feed member, theimprovement comprising secondary control means for automaticallycontrolling the feeding operation of the feed member depending upon thelocation of the top of said stack, said control means including a latchlever, means operatively connecting said latch lever to said feedmember, said latch lever moving with said feed member as the feed memberchanges position in response to a change in the height of said stack,the movement of the latch lever resulting in engagement of the latchlever with the means for driving said feed member when the top of thestack reaches a predetermined position, the engagement of the latchlever with the means for driving the feed member stopping the driving ofthe feed member.
 2. A mechine in accordance with claim 1 including asupport for said feed member, said means operatively connecting saidlatch lever including said support, and said support being movable withsaid feed member as the feed member moves in response to changes inlocation of the top of said stack.
 3. A machine in accordance with claim2 wherein said feed member comprises at least one feed roller, saidsupport comprising means for journalling the feed roller, said drivemeans including a clutch whereby said feed roller is adapted to rotatein only one direction for achieving successive feeding of the individualsheets.
 4. A construction in accordance with claim 3 wherein said drivemeans include a cam and a drive lever, the cam engaging one end of saiddrive lever, said cam imparting pivoting movement to said drive leverduring each rotation of the cam, gear means operatively connected tosaid drive lever whereby rotary movement is imparted to said gear meansduring pivoting movement of the drive lever, said gear means beingconnected to said feed roller through said clutch means.
 5. A machine inaccordance with claim 4 wherein said latch lever is adapted to move intoengagement with said drive lever, said latch lever preventing pivotingmovement of said drive lever when engaged with the drive lever.
 6. Amachine in accordance with claim 1 wherein said feed member graduallyfollows the top of said stack as the location of the top of said stackchanges upon removal of successive sheets from the stack.
 7. A machinein accordance with claim 1 wherein said table is adjustably mounted,said feed member moving in response to lowering of the table duringreplacement of paper on the table whereby said feed member stopsoperation when the table is lowered, and wherein said latch lever isautomatically disengaged when the table is raised after replacement ofpaper on the table.
 8. In a duplicating machine including a table forholding a stack of paper sheets, at least one feed member for engagingindividual sheets to feed the sheets to the duplicating mechanisms,means for driving the feed member for achieving the feeding operation,and primary means for controlling the operation of the means for drivingthe feed member, the improvement comprising means for automaticallycontrolling the feeding operation of the feed member depending upon thelocation of the top of said stack, said control means including a latchlever, a support for said feed member, said latch lever being connectedto the support and said support and latch lever being movable with saidfeed member as the feed member moves in response to changes in locationof the top of said stack, the movement of the latch lever resulting inengagement of the latch lever with the means for driving said feedmember when the top of the stack reaches a predetermined position, theengagement of the latch lever with the means for driving the feed memberstopping the feeding operation, and wherein said means connecting saidlatch lever to said support comprises position control lever meansmovable with said support, said position control lever means includingadjusting means for varying the relative positions of said support andsaid latch lever to thereby vary the predetermined position at whichsaid latch lever engages said means for driving said feed member.
 9. Amachine in accordance with claim 8 wherein said position control levermeans include a first lever, spring means urging said first leveragainst said support, and an adjustable screw carried by the support forvarying the relative position of said first lever and the support.
 10. Amachine in accordance with claim 9 including an additional adjustingscrew carried by said latch lever, a second position control leverengaging said additional adjusting screw, and additional spring meansconnecting said second position control lever and said latch lever, saidadditional adjusting screw operating to vary the relative positions ofsaid second position control lever and said latch lever in opposition tosaid additional spring means.
 11. In a duplicating machine including atable for holding a stack of paper sheets, at least one feed member forengaging individual sheets to feed the sheets to the duplicatingmechanisms, means for driving the feed member for achieving the feedingoperation, and primary means for controlling the operation of the meansfor driving the feed member, the improvement comprising means forautomatically controlling the feeding operation of the feed memberdepending upon the location of the top of said stack, said control meansincluding a latch lever, a support for said feed member, said latchlever being connected to the support and said support and latch leverbeing movable with said feed member as the feed member moves in responseto changes in location of the top of said stack, said feed membercomprising at least one feed roller, said support comprising means forjournalling the feed roller, said drive means including a clutch wherebysaid feed roller is adapted to rotate in only one direction forachieving successive feeding of the individual sheets, the movement ofthe latch lever resulting in engagement of the latch lever with themeans for driving said feed member when the top of the stack reaches apredetermined position, the engagement of the latch lever with the meansfor driving the feed member stopping the driving of the feed member,said means for driving including a cam and a drive lever, the camengaging one end of said drive lever, said cam imparting pivotingmovement to said drive lever during each rotation of the cam, gear meansoperatively connected to said drive lever whereby rotary movement isimparted to said gear means during pivoting movement of the drive lever,said gear means being connected to said feed roller through said clutchmeans, said gear means including a reciprocally movable segment gear, adrive arm connected to said drive lever for imparting driving force tothe segment gear, and means for adjusting the effective length of saiddrive arm to thereby vary the angular rotation of the segment gear forin turn varying the feed rotation of said feed roller.
 12. In aduplicating machine including a table for holding a stack of papersheets, at least one feed member for engaging individual sheets to feedthe sheets to the duplicating mechanisms, means for driving the feedmember for achieving the feeding operation, and primary means forcontrolling the operation of the means for driving the feed member, theimprovement comprising secondary control means for automaticallycontrolling the feeding operation of the feed member depending upon thelocation of the top of said stack, said control means including a latchlever, means operatively connecting said latch lever to said feedmember, said latch lever moving with said feed member as the feed memberchanges position in response to a change in the height of said stack,the movement of the latch lever resulting in disengagement of the latchlever with the means for driving said feed member when the top of thestack reaches a predetermined position, the disengagement of the latchlever with the means for driving the feed member starting the driving ofthe feed member.
 13. A machine in accordance with claim 12 including asupport for said feed member, said means operatively connecting saidlatch lever including said support, and said support being movable withsaid feed member as the feed member moves in response to changes inlocation of the top of said stack.
 14. A machine in accordance withclaim 13 wherein said feed member comprises at least one feed roller,said support comprising means for journalling the feed roller, saiddrive means including a clutch whereby said feed roller is adapted torotate in only one direction for achieving successive feeding of theindividual sheets.
 15. A construction in accordance with claim 14wherein said drive means include a cam and a drive lever, the camengaging one end of said drive lever, said cam imparting pivotingmovement to said drive lever during each rotation of the cam, gear meansoperatively connected to said drive lever whereby rotary movement isimparted to said gear means during pivoting movement of the drive lever,said gear means being connected to said feed roller through said clutchmeans.
 16. A machine in accordance with claim 15 wherein said latchlever is adapted to move into engagement with said drive lever, saidlatch lever preventing pivoting movement of said drive lever untildisengaged from the drive lever.
 17. A machine in accordance with claim12 wherein said feed member gradually follows the top of said stack asthe location of the top of said stack changes upon removal of successivesheets from the stack.
 18. A machine in accordance with claim 12 whereinsaid table is adjustably mounted, said feed member moving in response tolowering of the table during replacement of paper on the table wherebysaid feed member stops operation when the table is lowered, and whereinsaid latch lever is automatically disengaged when the table is raisedafter replacement of paper on the table.
 19. In a duplicating machineincluding a table for holding a stack of paper sheets, at least one feedmember for engaging individual sheets to feed the sheets to theduplicating mechanisms, means for driving the feed member for achievingthe feeding operation, and primary means for controlling the operationof the means for driving the feed member, the improvement comprisingmeans for automatically controlling the feeding operation of the feedmember depending upon the location of the top of said stack, saidcontrol means including a latch lever, a support for said feed member,said latch lever being connected to the support and said support andlatch lever being movable with said feed member as the feed member movesin response to changes in location of the top of said stack, themovement of the latch lever resulting in disengagement of the latchlever with the means for driving said feed member when the top of thestack reaches a predetermined position, the disengagement of the latchlever with the means for driving the feed member starting the driving ofthe feed member, and wherein said means connecting said latch lever tosaid support comprises position control lever means movable with saidsupport, said position control lever means including adjusting means forvarying the relative positions of said support and said latch lever tothereby vary the predetermined position at which said latch leverengages said means for driving said feed member.
 20. A machine inaccordance with claim 19 wherein said position control lever meansinclude a first lever, spring means urging said first lever against saidsupport, and an adjustable screw carried by the support for varying therelative position of said first lever and the support.
 21. A machine inaccordance with claim 20 including an additional adjusting screw carriedby said latch lever, a second position control lever engaging saidadditional adjusting screw, and additional spring means connecting saidsecond position control lever and said latch lever, said additionaladjusting screw operating to vary the relative positions of said secondposition control lever and said latch lever in opposition to saidadditional spring means.
 22. In a duplicating machine including a tablefor holding a stack of paper sheets, at least one feed member forengaging individual sheets to feed the sheets to the duplicatingmechanisms, means for driving the feed member for achieving the feedingoperation, and primary means for controlling the operation of the meansfor driving the feed member, the improvement comprising means forautomatically controlling the feeding operation of the feed memberdepending upon the location of the top of said stack, said control meansincluding a latch lever, a support for said feed member, said latchlever being connected to the support and said support and latch leverbeing movable with said feed member as the feed member moves in responseto changes in location of the top of said stack, said feed membercomprising at least one feed roller, said support comprising means forjournalling the feed roller, said drive means including a clutch wherebysaid feed roller is adapted to rotate in only one direction forachieving successive feeding of the individual sheets, the movement ofthe latch lever resulting in disengagement of the latch lever with themeans for driving said feed member when the top of the stack reaches apredetermined position, the disengagement of the latch lever with themeans for driving the feed member starting the driving of the feedmember, said means for driving including a cam and a drive lever, thecam engaging one end of said drive lever, said cam imparting pivotingmovement to said drive lever during each rotation of the cam, gear meansoperatively connected to said drive lever whereby rotary movement isimparted to said gear means during pivoting movement of the drive lever,said gear means being connected to said feed roller throUgh said clutchmeans, said gear means including a reciprocally movable segment gear, adrive arm connected to said drive lever for imparting driving force tothe segment gear, and means for adjusting the effective length of saiddrive arm to thereby vary the angular rotation of the segment gear forin turn varying the feed rotation of said feed roller.